Question

已知x=2的m次方+1 ，Y=3+4的m次方。请用含X的代数式表示y

八年级上

Answer 1

x=2^m+1
2^m=x-1
两边平方
(2^m)^2=(x-1)^2
4^m=(x-1)^2

y=3+4^m
4^m=y-3
所以y-3=(x-1)^2
y=(x-1)^2+3
即y=x^2-2x+4

Answer 2

m=log (x-1)
2

再把代入y中

Answer 3

X=2^M+1 M=log(2) (X-1)
Y=3+4^M 把M代入 及得Y=3+2^(X-1)

Answer 4

x=2^m+1
x-1=2^m
(x-1)^2=(2^m)^2=4^m=y-3
y=(x-1)^2+3

Answer 5

x=2^m+1
2^m=x-1

y=3+4^m=(2^m)^2+3=(x-1)^2+3=x^2-2x+4

y=x^2-2x+4

Answer 6

两式相减：y-x=3+(2^m)-(2^(m+1))